The present disclosure relates to an electric motor-driven truck.
A driver of a vehicle changes step from a brake pedal to an accelerator pedal when starting the vehicle on a slope. JP2014-166053A discloses a technique that in order to prevent an electric motor-driven vehicle from descending and retreating on a slope during the changing step, torque is generated in accordance with the gradient amount of the slope.
The retreating force acting in a retreating direction on an uphill is influenced by not only the gradient amount of the slope but also a vehicle weight. However, the disclosure in the prior art document does not mention the vehicle weight. It is considered that this is because the disclosure in the above technique is based on the assumption that the vehicle weight is nearly constant. When general passenger vehicles are targeted, a problem would not be raised even based on such assumption because the variation width of a vehicle weight is not large.
However, in the case of trucks, the variation width of a vehicle weight is considerably larger than the case of passenger vehicles due to a loaded freight amount. Thus, when the above-described assumption is adopted, the excess or shortage of torque may occur. Measuring or estimating a vehicle weight and considering a vehicle weight, it is possible to use the method in the above technique. However, such measurement or estimation requires time and effort or complicated arithmetic operation. Thus, it is preferable to avoid such measurement or estimation.
Therefore, there is need facilitating an electric motor-driven truck to start on a slope by an easy method.